1. Field of the Invention
The present invention relates to a straddle type vehicle such as a motorcycle.
2. Description of Related Art
Usually, exhaust gas from an engine of a straddle type vehicle is emitted to the air. The exhaust gas should be purified as much as possible before emission to the air. Therefore, a catalytic converter (catalyzer) is conventionally provided midway in an exhaust conduit through which exhaust gas is emitted to carry out purification (for example, see JP-A-2001-130474).
In the conventional art, to effectively purify exhaust gas, a secondary air inducting conduit is mounted upstream of the catalyzer, and outside (secondary) air is inducted from the secondary air inducting conduit through the exhaust conduit to the catalyzer. Combustion efficiency of exhaust gas is thereby enhanced by passing secondary air through the catalyzer.
However, in the conventional art, the secondary air inducting conduit extends downward from an air cleaner toward the exhaust conduit and is covered from the front and the side by a vehicle cover. The vehicle cover hinders high temperature heat from being emitted outside, and the high temperature heat is therefore apt to directly transmit to the secondary air inducting conduit.
As a result, there is a problem that oxygen in secondary air flowing through the secondary air inducting conduit expands due to heat from the engine, which lowers oxygen concentration lowers and makes it difficult to enhance combustion efficiency of the exhaust gas by secondary air in the catalyzer.